<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>downloadmanager.cpp Example File | Qt Network 5.12.6</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.12</td><td ><a href="qtnetwork-index.html">Qt Network</a></td><td ><a href="qtnetwork-downloadmanager-example.html">Network Download Manager Example</a></td><td >downloadmanager.cpp Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtnetwork-index.html">Qt 5.12.6 Reference Documentation</a></td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"><div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">downloadmanager.cpp Example File</h1> <span class="subtitle">downloadmanager/downloadmanager.cpp</span> <!-- $$$downloadmanager/downloadmanager.cpp-description --> <div class="descr"> <a name="details"></a> <pre class="cpp"> <span class="comment">/**************************************************************************** ** ** Copyright (C) 2017 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:BSD$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** BSD License Usage ** Alternatively, you may use this file under the terms of the BSD license ** as follows: ** ** "Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions are ** met: ** * Redistributions of source code must retain the above copyright ** notice, this list of conditions and the following disclaimer. ** * Redistributions in binary form must reproduce the above copyright ** notice, this list of conditions and the following disclaimer in ** the documentation and/or other materials provided with the ** distribution. ** * Neither the name of The Qt Company Ltd nor the names of its ** contributors may be used to endorse or promote products derived ** from this software without specific prior written permission. ** ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." ** ** $QT_END_LICENSE$ ** ****************************************************************************/</span> <span class="preprocessor">#include "downloadmanager.h"</span> <span class="preprocessor">#include <QTextStream></span> <span class="preprocessor">#include <cstdio></span> <span class="keyword">using</span> <span class="keyword">namespace</span> std; DownloadManager<span class="operator">::</span>DownloadManager(<span class="type"><a href="../qtcore/qobject.html">QObject</a></span> <span class="operator">*</span>parent) : <span class="type"><a href="../qtcore/qobject.html">QObject</a></span>(parent) { } <span class="type">void</span> DownloadManager<span class="operator">::</span>append(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstringlist.html">QStringList</a></span> <span class="operator">&</span>urls) { <span class="keyword">for</span> (<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&</span>urlAsString : urls) append(<span class="type"><a href="../qtcore/qurl.html">QUrl</a></span><span class="operator">::</span>fromEncoded(urlAsString<span class="operator">.</span>toLocal8Bit())); <span class="keyword">if</span> (downloadQueue<span class="operator">.</span>isEmpty()) <span class="type"><a href="../qtcore/qtimer.html">QTimer</a></span><span class="operator">::</span>singleShot(<span class="number">0</span><span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SIGNAL(finished())); } <span class="type">void</span> DownloadManager<span class="operator">::</span>append(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qurl.html">QUrl</a></span> <span class="operator">&</span>url) { <span class="keyword">if</span> (downloadQueue<span class="operator">.</span>isEmpty()) <span class="type"><a href="../qtcore/qtimer.html">QTimer</a></span><span class="operator">::</span>singleShot(<span class="number">0</span><span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(startNextDownload())); downloadQueue<span class="operator">.</span>enqueue(url); <span class="operator">+</span><span class="operator">+</span>totalCount; } <span class="type"><a href="../qtcore/qstring.html">QString</a></span> DownloadManager<span class="operator">::</span>saveFileName(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qurl.html">QUrl</a></span> <span class="operator">&</span>url) { <span class="type"><a href="../qtcore/qstring.html">QString</a></span> path <span class="operator">=</span> url<span class="operator">.</span>path(); <span class="type"><a href="../qtcore/qstring.html">QString</a></span> basename <span class="operator">=</span> <span class="type"><a href="../qtcore/qfileinfo.html">QFileInfo</a></span>(path)<span class="operator">.</span>fileName(); <span class="keyword">if</span> (basename<span class="operator">.</span>isEmpty()) basename <span class="operator">=</span> <span class="string">"download"</span>; <span class="keyword">if</span> (<span class="type"><a href="../qtcore/qfile.html">QFile</a></span><span class="operator">::</span>exists(basename)) { <span class="comment">// already exists, don't overwrite</span> <span class="type">int</span> i <span class="operator">=</span> <span class="number">0</span>; basename <span class="operator">+</span><span class="operator">=</span> <span class="char">'.'</span>; <span class="keyword">while</span> (<span class="type"><a href="../qtcore/qfile.html">QFile</a></span><span class="operator">::</span>exists(basename <span class="operator">+</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span><span class="operator">::</span>number(i))) <span class="operator">+</span><span class="operator">+</span>i; basename <span class="operator">+</span><span class="operator">=</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span><span class="operator">::</span>number(i); } <span class="keyword">return</span> basename; } <span class="type">void</span> DownloadManager<span class="operator">::</span>startNextDownload() { <span class="keyword">if</span> (downloadQueue<span class="operator">.</span>isEmpty()) { printf(<span class="string">"%d/%d files downloaded successfully\n"</span><span class="operator">,</span> downloadedCount<span class="operator">,</span> totalCount); <span class="keyword">emit</span> finished(); <span class="keyword">return</span>; } <span class="type"><a href="../qtcore/qurl.html">QUrl</a></span> url <span class="operator">=</span> downloadQueue<span class="operator">.</span>dequeue(); <span class="type"><a href="../qtcore/qstring.html">QString</a></span> filename <span class="operator">=</span> saveFileName(url); output<span class="operator">.</span>setFileName(filename); <span class="keyword">if</span> (<span class="operator">!</span>output<span class="operator">.</span>open(<span class="type"><a href="../qtcore/qiodevice.html">QIODevice</a></span><span class="operator">::</span>WriteOnly)) { fprintf(stderr<span class="operator">,</span> <span class="string">"Problem opening save file '%s' for download '%s': %s\n"</span><span class="operator">,</span> <a href="../qtcore/qtglobal.html#qPrintable">qPrintable</a>(filename)<span class="operator">,</span> url<span class="operator">.</span>toEncoded()<span class="operator">.</span>constData()<span class="operator">,</span> <a href="../qtcore/qtglobal.html#qPrintable">qPrintable</a>(output<span class="operator">.</span>errorString())); startNextDownload(); <span class="keyword">return</span>; <span class="comment">// skip this download</span> } <span class="type"><a href="qnetworkrequest.html">QNetworkRequest</a></span> request(url); currentDownload <span class="operator">=</span> manager<span class="operator">.</span>get(request); connect(currentDownload<span class="operator">,</span> SIGNAL(downloadProgress(<span class="type"><a href="../qtcore/qtglobal.html#qint64-typedef">qint64</a></span><span class="operator">,</span><span class="type"><a href="../qtcore/qtglobal.html#qint64-typedef">qint64</a></span>))<span class="operator">,</span> SLOT(downloadProgress(<span class="type"><a href="../qtcore/qtglobal.html#qint64-typedef">qint64</a></span><span class="operator">,</span><span class="type"><a href="../qtcore/qtglobal.html#qint64-typedef">qint64</a></span>))); connect(currentDownload<span class="operator">,</span> SIGNAL(finished())<span class="operator">,</span> SLOT(downloadFinished())); connect(currentDownload<span class="operator">,</span> SIGNAL(readyRead())<span class="operator">,</span> SLOT(downloadReadyRead())); <span class="comment">// prepare the output</span> printf(<span class="string">"Downloading %s...\n"</span><span class="operator">,</span> url<span class="operator">.</span>toEncoded()<span class="operator">.</span>constData()); downloadTime<span class="operator">.</span>start(); } <span class="type">void</span> DownloadManager<span class="operator">::</span>downloadProgress(<span class="type"><a href="../qtcore/qtglobal.html#qint64-typedef">qint64</a></span> bytesReceived<span class="operator">,</span> <span class="type"><a href="../qtcore/qtglobal.html#qint64-typedef">qint64</a></span> bytesTotal) { progressBar<span class="operator">.</span>setStatus(bytesReceived<span class="operator">,</span> bytesTotal); <span class="comment">// calculate the download speed</span> <span class="type">double</span> speed <span class="operator">=</span> bytesReceived <span class="operator">*</span> <span class="number">1000.0</span> <span class="operator">/</span> downloadTime<span class="operator">.</span>elapsed(); <span class="type"><a href="../qtcore/qstring.html">QString</a></span> unit; <span class="keyword">if</span> (speed <span class="operator"><</span> <span class="number">1024</span>) { unit <span class="operator">=</span> <span class="string">"bytes/sec"</span>; } <span class="keyword">else</span> <span class="keyword">if</span> (speed <span class="operator"><</span> <span class="number">1024</span><span class="operator">*</span><span class="number">1024</span>) { speed <span class="operator">/</span><span class="operator">=</span> <span class="number">1024</span>; unit <span class="operator">=</span> <span class="string">"kB/s"</span>; } <span class="keyword">else</span> { speed <span class="operator">/</span><span class="operator">=</span> <span class="number">1024</span><span class="operator">*</span><span class="number">1024</span>; unit <span class="operator">=</span> <span class="string">"MB/s"</span>; } progressBar<span class="operator">.</span>setMessage(<span class="type"><a href="../qtcore/qstring.html">QString</a></span><span class="operator">::</span>fromLatin1(<span class="string">"%1 %2"</span>) <span class="operator">.</span>arg(speed<span class="operator">,</span> <span class="number">3</span><span class="operator">,</span> <span class="char">'f'</span><span class="operator">,</span> <span class="number">1</span>)<span class="operator">.</span>arg(unit)); progressBar<span class="operator">.</span>update(); } <span class="type">void</span> DownloadManager<span class="operator">::</span>downloadFinished() { progressBar<span class="operator">.</span>clear(); output<span class="operator">.</span>close(); <span class="keyword">if</span> (currentDownload<span class="operator">-</span><span class="operator">></span>error()) { <span class="comment">// download failed</span> fprintf(stderr<span class="operator">,</span> <span class="string">"Failed: %s\n"</span><span class="operator">,</span> <a href="../qtcore/qtglobal.html#qPrintable">qPrintable</a>(currentDownload<span class="operator">-</span><span class="operator">></span>errorString())); output<span class="operator">.</span>remove(); } <span class="keyword">else</span> { <span class="comment">// let's check if it was actually a redirect</span> <span class="keyword">if</span> (isHttpRedirect()) { reportRedirect(); output<span class="operator">.</span>remove(); } <span class="keyword">else</span> { printf(<span class="string">"Succeeded.\n"</span>); <span class="operator">+</span><span class="operator">+</span>downloadedCount; } } currentDownload<span class="operator">-</span><span class="operator">></span>deleteLater(); startNextDownload(); } <span class="type">void</span> DownloadManager<span class="operator">::</span>downloadReadyRead() { output<span class="operator">.</span>write(currentDownload<span class="operator">-</span><span class="operator">></span>readAll()); } bool DownloadManager<span class="operator">::</span>isHttpRedirect() <span class="keyword">const</span> { <span class="type">int</span> statusCode <span class="operator">=</span> currentDownload<span class="operator">-</span><span class="operator">></span>attribute(<span class="type"><a href="qnetworkrequest.html">QNetworkRequest</a></span><span class="operator">::</span>HttpStatusCodeAttribute)<span class="operator">.</span>toInt(); <span class="keyword">return</span> statusCode <span class="operator">=</span><span class="operator">=</span> <span class="number">301</span> <span class="operator">|</span><span class="operator">|</span> statusCode <span class="operator">=</span><span class="operator">=</span> <span class="number">302</span> <span class="operator">|</span><span class="operator">|</span> statusCode <span class="operator">=</span><span class="operator">=</span> <span class="number">303</span> <span class="operator">|</span><span class="operator">|</span> statusCode <span class="operator">=</span><span class="operator">=</span> <span class="number">305</span> <span class="operator">|</span><span class="operator">|</span> statusCode <span class="operator">=</span><span class="operator">=</span> <span class="number">307</span> <span class="operator">|</span><span class="operator">|</span> statusCode <span class="operator">=</span><span class="operator">=</span> <span class="number">308</span>; } <span class="type">void</span> DownloadManager<span class="operator">::</span>reportRedirect() { <span class="type">int</span> statusCode <span class="operator">=</span> currentDownload<span class="operator">-</span><span class="operator">></span>attribute(<span class="type"><a href="qnetworkrequest.html">QNetworkRequest</a></span><span class="operator">::</span>HttpStatusCodeAttribute)<span class="operator">.</span>toInt(); <span class="type"><a href="../qtcore/qurl.html">QUrl</a></span> requestUrl <span class="operator">=</span> currentDownload<span class="operator">-</span><span class="operator">></span>request()<span class="operator">.</span>url(); <span class="type"><a href="../qtcore/qtextstream.html">QTextStream</a></span>(stderr) <span class="operator"><</span><span class="operator"><</span> <span class="string">"Request: "</span> <span class="operator"><</span><span class="operator"><</span> requestUrl<span class="operator">.</span>toDisplayString() <span class="operator"><</span><span class="operator"><</span> <span class="string">" was redirected with code: "</span> <span class="operator"><</span><span class="operator"><</span> statusCode <span class="operator"><</span><span class="operator"><</span> <span class="char">'\n'</span>; <span class="type"><a href="../qtcore/qvariant.html">QVariant</a></span> target <span class="operator">=</span> currentDownload<span class="operator">-</span><span class="operator">></span>attribute(<span class="type"><a href="qnetworkrequest.html">QNetworkRequest</a></span><span class="operator">::</span>RedirectionTargetAttribute); <span class="keyword">if</span> (<span class="operator">!</span>target<span class="operator">.</span>isValid()) <span class="keyword">return</span>; <span class="type"><a href="../qtcore/qurl.html">QUrl</a></span> redirectUrl <span class="operator">=</span> target<span class="operator">.</span>toUrl(); <span class="keyword">if</span> (redirectUrl<span class="operator">.</span>isRelative()) redirectUrl <span class="operator">=</span> requestUrl<span class="operator">.</span>resolved(redirectUrl); <span class="type"><a href="../qtcore/qtextstream.html">QTextStream</a></span>(stderr) <span class="operator"><</span><span class="operator"><</span> <span class="string">"Redirected to: "</span> <span class="operator"><</span><span class="operator"><</span> redirectUrl<span class="operator">.</span>toDisplayString() <span class="operator"><</span><span class="operator"><</span> <span class="char">'\n'</span>; } </pre> </div> <!-- @@@downloadmanager/downloadmanager.cpp --> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2019 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners. </p> </div> </body> </html>